Safety arming device



Jilly 29, 1958" R'. EREENE, JR 2,

SAFETY ARMING DEVICE 2 Sheets-Sheet 1 Filed Jan. 8, 1953 FICA,

INVENTOR ROBERT E. GREENE JR.

ATTORNEYS .2',84s; 24 SAFETY AR'MINGDEVICE Ro r cream, il e inaMda ig to the V United States of America :asrepresented by the Secretary (if theNavy... r

i Application-January 1953, Serial .No. 330,3 67

' T3Clairns. c1.1 02 4 f (Granted-under Title-35, U. s. Code 1952 see. 266) The invention' descrihed hereinmay be manufactured and 'used by ornforithe Government of the United States of America for .governmental purposes without 'the payment of any .royalti'eszthereo'n .or therefor.

' The present invention'relates tosanaapparatus for ensuring.thepropers'equence of operation during the re- .rnoval of :a safety pin land the insertion of an arming Wire #ofa time delayicontrolyunit for releasing the .cover of {a parachute-ipack or for performing other'such oper- .-ations in ordnance devices;

Prior art control units-:havehad.znopprovision for ensuring'suchproper sequential operation; thus, the safety in may beremovedipriorrtoiinscr ioni of the armin W which causes the -.de.vi,c,e tovarm prematurely resulting -in improperoperationoftheunit.-

In the device-"ofthe present invention a safety pin is provided whichcannot \be remoVfid'without exerting great force until the arming wire inserted whereupon re- ..-sistance to the removal :of the safety pin is reduced-permitting withdrawal :t-hQNQf. r

- An objectef the -present invention is to provide new and improved apparatus for preventing premature armn ie on mlh Qr rd ane z vi by resisting removal of; a safety pin from "the unit until such resistancehas beenreleasedhy thelinsertion of .an arming wire i-nthe-unit. a

t lS 1O:PI0S/lde"l16W ;?1nd improved ap- An he bi paratusfonretaining the safety pinof anqordnance de- 7 vice .aigainst rernoval untilan arming wire has :been 'in-' I serted in thedevicethus tb-ensureproper operation'of thedevice. a i

Still another object is to provide apparatus for the control unit, of an ordnance; device wherein safety to personnel an'dproper sequential operation of the unit is assured.

@Q obia s and .m ry qfitha t n a ed this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with V the accompanying drawings wherein:

Fig. 1 is a rear elevation of aparachute pack showing control .unit mounted therein;

vice and showing the respective positions of the components and the safety pin when the arming wire isinserted;

V Fig. .5 is a view similar to Fig. 4 and showing the 7 respective positions of the components and the arming wire; and,

Fig. 6is a sectional View takenalong the line 66 of V Fig. 5 and showing the therefrom. I

- Referring more particularly to the drawings wherein safety pin'free for withdrawal {like numerals 'indicatelike parts throughout the several views, 10 indicates generally'a parachute pa'ck in which *the control device '11 is mounted. Pack '10 is provided in the present case with a fin 'structure12; Control de- 5 'v'ic'e 11 'is provided'with a mechanical delay switch hav- ;in g"a casing 13 fitted with a cover 14 which has rem-ed thereon a-cdllar '15. Fixedly mounted in' c o llar "1' 5 is'a tubular member '16 having a flange 17 formed thereon for preventing movement thereof in an outward "direction 10 and having an O ring gasket 18 interposed between the flange P17 and "the inner side of 'cover 1 4. Bore19fof member 16 receives slidably a firingp in .Tubular I member 16 is held ,against movement in an'inward "direction' by locking ring 22 which is mounted in groove 23 of member 1 6 as clearly shownfin Fig. 2.

Cover 14 is" provided with a tubular portion 24. =extendinginwardl-y therefrom and in axial alignment with collar '15- and coaxial with 'pin '21 and tubular member r 16. Slidably mounted in portion 24 is a cylindrical rack 'ZS'haV-ing circumferential gearfteeth 26 formed on'the outer suffatze-thcreof. A-n inwardly eixtendingcircum- 'ferential flange'27 is formedon the inner'surface ofrack and engages the flange 28 of a spring cup '2 9'sec'u'red to the inner end of pin 21. Interposed between flange 17-of tubular member -16 and "spring cup=29 isia helical spring 31 which exerts a force to move pinfl2-1 toward :a primer .32 as will be h'ere'inafter more ruuy described.

, A second helical spring 33 :of-larger diameter'th'anis'pr'ing' 3&1 'is mounted between the inner face of cover '14 -and y-fla-nge?2Toffi1iakl25 and exerts a force to inove r'ak 25 in aidirection toward switch. .34" mounted-'interiorly or the time delay switch-casing-13- 1 A ,gear train 35 is mounted lin casing lfa and has ing corporated. therein an escapement mecha'nism or other retarding apparatus :36. "Pinion 37 of gear train-35 meshes with' teeth 26 ofrack 25. .Spring cup .25! l'SifidjllSlflblYSfiCllTBdOIl reducedthre'aded end138of .pin zl by a lock nut-39 of any'suitable vari'ety. The extreme end .141 of pin 21 is pointed to -'ensur penetration of the primer 32 thereby. J i a u V In order to maintain pin Z'Irin an armed position and vto retain springs 31and-33'in .the compressed condition 1;.the're1o'f :a safety pin 42 is .provided, pin 42' 'being ro- -yided1 with threads .43, along the length thereofgand an 45 '.ey e 44 at one end thereof for receiving an instruction Firing pin 21 is provided with a circumferential groove ;46; .of suflicient size to receive "pin 42 therein. Eubular member 16 has formed therein a pair'of Ithreadedaligned bores 47,; the threads beingof'the same number per inch a as .the threads ofpin 42andof a 'diameter'to'pennit ,pin

42 to pass freely therethrough without rotation. also passes through smooth bores 48 of annular member 49 which is sleeved about the outer end of tubular member 16. Annular member 49 is also provided with a slot 51 aligned with the other side of groove '46 of firing pin 21 and a pair of bores 52-in tubular member 16. Bores 52, slot 51 and the other side of groove 46 of firing pin 21 are adapted to receive an arming wire 53 having a tapered end 54.

As shown in Fig.4 pin 42 is urged in a direction 7 Q towardcover 14 by the wall of groove 46 inpin 21 which in turn is urged inwardly by the high tension'ofsprings 31 and 33. Threads 43 of pin 42 rest in one side of threaded bores 47 thus locking and preventing removal of safety pin 42 by the usual method of hand withdrawal until the arming wire 53 is inserted through slot 51 and bores 52; Bores 52 are slightly; offset with respect to groove 46 of pin 21 to cause acamming action as'the tapered end 54 of arming wire 53 contacts andpasses through groove 46 thus lifting pin 21 againstthetension .of springs 31 and 33, releasing tension on safety. pin 42 p 2,845,024 "f Pate nte d .ItilyeZQ,

Pin 42 vided with a corresponding slot opposite slot 51.

and centering'the pin 42 in threaded bores 47, thus freeing safety pin 42 for easy withdrawal from the device.

It will be noted that annular member 49 is not pro- This is to prevent arming wire 53 from passing completely through the bores and into the usual armed position thereof until safety pin 42 is removed from bores 48 in annular' member 49. After pin 42 is withdrawn, annular member 49 is free to be removed from tubular member 16. When member 49 is removed, arming wire 53 is forced through bores 52 and groove 46 until a required length of the free end thereof has passed therethrough.

From the foregoing it is clear that there has been provided an apparatus for preventing withdrawal of safety pin 42 until arming wire 53 has been inserted thus preventing premature operation of a parachute pack cover release circuit. When the mine is released from an aircraft, arming wire 53 is withdrawn causing firing pin 21 to strike primer 32, the primer causing a source of electrical energy (not shown) to be activated. When firing pin 21'is released, rack 25 is released thereby and is retarded in its movement toward switch 34 by gear 1 train 35 and escapement 36 to provide a predetermined time delay between activation of the energy source and closing of switch 34. Switch 34 is closed as rack 25 approaches the end of its movement, finger 55 of leaf spring 56 being engaged by the rack 25 thus causing contact 57 thereof to engage contact 58 of fixed arm 59 of the switch. When the contacts 57 and 58 engage, the circuit for releasing the cover of the parachute pack is energized thus releasing the cover.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

, What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In an arming device/a fixed member, a movable member slidably mounted in said fixed member, a trans- ,verse bore in said fixed member, a safety pin freely received in said bore, spring means biasing said movable member for movement in one direction, means on said movable member engaged by said pin for preventing movement of said movable member in said one direc- -tion, interlocking means on said pin and on said fixed wire serving to prevent movement of the movable member by said spring means until the arming wire is withdrawn, and a removable annular member sleeved about said fixed member and engageable by said pin to prevent removal of the annular member, said annular member having means for preventing'complete insertion of the arming Wire until said pin is withdrawn.

2. In an arming device, a casing having a fixed tubular member secured through a wall thereo, a cylindrical firing pin slidably mounted in said fixed member and having a retracted position and a firing position, a transverse threaded bore and a smooth bore in said fixed member, a threaded safety pin extending through said threaded bore, the internal diameter of said threaded bore being greater than the external diameter of said safety pin whereby the safety pin is adapted to be freely movable in the threaded bore, means on said firing pin engageable by said safety pinto prevent movement of said firing pin from the retracted position thereof, means for yieldably urging said firing pin in one direction whereby a biasing effect is exerted on said safety pin and the threads of said safety pin lockingly engage the threads of said threaded bore, and an arming wire insertable in said smooth bore and engageable with said firing pin, insertion of said arming wire serving to move said firing pin and relieve the biasing effect exerted on said safety pin whereby the safety pin is freely movable for withdrawal from said threaded bore.

ber, a threaded safety pin extending through said bore,

the diameter of said safety pin being less than the internal diameter of said'threaded bore, the threads of the safety pin and the bore being of the same pitch, said firing pin being formed with a circumferential groove and thereby providing a shoulder on said firing pin in engagement with said safety pin, said firing pin having a biasing effect on said safety pin so that the threads of "the safety pin and the threads of the bore interengage to prevent withdrawal of the safety pin, a second bore in said tubular member for receiving an arming wire, said second bore having the axis thereof offset with respect to the axis of said first bore whereby the biasing effect 'of the firing pin on the safety pin is relieved as the arm-' ing wire engages the shoulder of said firing pin to permit withdrawal of the safety pin.

References Cited in the file of this patent UNITED STATES PATENTS 2,393,861 M-iller Jan. 29, 1946 

